7. It is to be borne in mind that one or more lymphatic glands usually lic in front of the artery imbedded in the cellular structure which forms its investment, and that these may be to be displaced.
8. In operations upon the iliac arteries, more particularly when performed after the method of Abernethy, or upon the internal or primi tive vessels, a protrusion or bearing down of the abdominal viscera is to be expected which has been found a great obstruction to the operation : this will be most effectually pre vented by the use of purgatives previous to the operation; by posture, the abdominal muscles being thereby relaxed as much as possible ; and during the operation, if it occur, by the use of curved spatulas of considerable width and curve, as used by Mott, with which the viscera may be supported.
9. In the passage of the ligature it will always be necessary to be assured that the genito-crural nerve is not included; but it may be avoided without difficulty, and can seldom require to be divided. Its situation should be borne in mind, viz. above external to the artery, below external or anterior.
Lastly, it would seem the safer plan to pass the needle and ligature from within outward, inasmuch as the vein is internal to the artery. In Cooper's Lectures edited by Tyrrell, it is directed to pass the needle from without ; by so doing there is less risk that the genito-crural nerve shall be included, and in high operations, since the vein is situate so much beneath the artery at the superior part of their course, it will not be thereby much endangered, but at the lower part the vein must certainly be more exposed by that mode of passing the ligature than by the contrary one, while the nerve may be avoided without difficulty.
We shall next consider the comparative merits of the several plans of operation. In the method of Abernethy the direction of the line of incision is attended with the following consequences. 1. It requires a more extensive division of the oblique and transversalis mus cles, and hence is more likely to be followed by weakness of the abdominal wall. 2. Fal ling, as first performed by him, nearly upon the course of the epigastrie artery, it exposes that vessel to be divided, though in the me thod adopted by him in his latter operations this risk must be very much diminished, if not removed. 3. The extent to which it is neces sary to divide the internal oblique and trans versalis muscles must expose the peritoneum lining the anterior wall of the abdomen to be lacerated or divided during their separation. 4. The parallelism of the vessel and the wound must render it necessary to expose a greater length of the former, in order to effect its separation from the contiguous parts and to pass a ligature round it. 5. It is therefore
necessary to detach the peritoneum in all cases, and to a greater extent than may be necessary or required by a different method. 6. The peritoneum must be detached to an equal ex tent from both walls of the abdomen—from the anterior as much as, or it may be more than, from the posterior. 7. The protrusion of the viscera must be more likely to occur.
It is asserted by some* that the spermatic cord is more exposed to injury in this method ; but it appears to me that it cannot be more so than in others, and that it ought to be more safe.
The second method is free from many objec tions to which others, and especially the first, are exposed. 1. It does not endanger any vessel but the superficial epigastric. 2. It does not endanger the spermatic cord. 3. Probably it does not tend to weaken the abdominal wall as much as the first method. 4. It renders necessary a much less extensive detachment of the peritoneum, since the line of incision falls so much nearer to the inferior reflection of the membrane. Add to these that by it the artery may be reached at as high a point as by the first, and no doubt can remain that it is to be preferred to it ; and in cases requiring a high ligature of the vessel there is none, save the modification of Cooper's method, which can be considered equally eligible. It is still, however, subject to the same conditions with the first, only in less degree. In the method of Cooper, on the contrary, the internal oblique and transversalis muscles are divided to but an inconsiderable extent, and the division of the aponeurosis of the external oblique approaches more to the course of its fibres. The direc tion of the incision being transverse to that of the artery, the vessel may be exposed, and a ligature passed round it without stripping it to a great extent and with little disturbance of it. Again, for the same reason and because of the vicinity of the incision to the crural arch, the vessel may be exposed either without dis placing the peritoneum at all, or displacing it but little ; and when it is necessary to displace the membrane, that may be effected with the least possible disturbance of it, inasmuch as, because of the propinquity of the line of in cision to the reflection of the membrane, it is not necessary to detach the latter from the anterior wall of the abdomen. It must also be less exposed to the protrusion of the viscera, and when the vessel is tied below, the reflection of the peritoneum must be exempt from it. This method permits the artery to be reached at from an inch to an inch and a half above the crural arch.